SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b11a455f595b8cd6622cd761d157091385a1fb9e9198267e01a23188dbf8e00' 
  AND token = 'pLNI0XRaSpNZXReppZtDsMtbL+RVrf5MwwjyD2aRXEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}